window.onbeforeunload = function() {
                   var scrollPos;
                   if(typeof window.pageYOffset != 'undefined') {
                        scrollPos = window.pageYOffset;
                   } else if(typeof document.compatMode != 'undefined' &&
                        document.compatMode != 'BackCompat') {
                        scrollPos = document.documentElement.scrollTop;
                   } else if(typeof document.body != 'undefined') {
                        scrollPos = document.body.scrollTop;
                   }
                   document.cookie = "scrollTop=" + scrollPos; //存储滚动条位置到cookies中
              }
//window.onload = function() {
////                   alert("jinlail");
//   if(document.cookie.match(/scrollTop=([^;]+)(;|$)/) != null) {
//        var arr = document.cookie.match(/scrollTop=([^;]+)(;|$)/); //cookies中不为空，则读取滚动条位置
////        alert(arr[1])
//         document.documentElement.scrollTop = parseInt(arr[1]);
//        document.body.scrollTop = parseInt(arr[1]);
//   }
//}